Hydraulic operated variable pitch propeller



4 Sheets-Sheet 1 N. 50 www 00 .mf /!.Y mJL. /M NT R EPV. m WEP T wf A @M R. J. RUTHS ET AL HYDRAULIC` OPERATED VARIABLE FITCH PRUPELLER Filed Aug. 10, 1938 Aug. 6, 1940.

Aug 6 l940- R. J. RUTHs Er A1. 2,210,009

HYDRAULIC OPERATED VARIABLE PITGHVPROPELLER Filed Au'g. 1o,L 193s '4 Smets-sheet 2 INVENTORS @caser J. fau-rus BY Haney L.oooson ATTORNEHm Aug 6, 1940 R. J. RuTHs ET AL HYDRAULIC OPERATED VARIABLE PITGHPROPELLER n Filed Aug. 10, 1958 4 Sheets-Sheet 3 INVENTORS eoaer J. @urns BY Harem' L ooosn R. J. Ru'rHs ET A1. HYDRAULIC OPERATED VARIABLE PITCH PROPELBER Filed Aug. 10, 1958 4 Sheets-Sheet 4 INVENToRs BERT Rvws am! L. Dobson Aug. 6, 1940.

ATTORNEY Patented Ang. 6, 1940 UNITED STATES Y HYDRAULIC OPERATED VARIABLE PITCH PBOPELLEB Robert J. Buths, Baltimore, Md., and Harry L. Dodson, United States Navy Application August 10, 1938, Serial No. 224,066

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(Cl. 17o- 163) (Granted under the act oi' March 3, 1883, as amended April 30, 1928; 370 0. G. 757) With these and other objects in view, as weilA as other advantages that may be incident to the use of the improvements, the invention consists in the parts and combinations thereof hereinafter set forth and claimed, with the understanding that the several necessary elements constituting the same may be varied in proportion and arrangement without departing from the nature and scope of the invention, as defined in the appended claims.

In order to make the invention more clearly understood, there are shown in the accompanying drawings, ineans for carrying the invention into practical use, withouflimiting the improvements in their useful application to the particular construction, which, for the purpose of explanation, have been made the subject of i1- lustration.

In the accompanying drawings:

Fig. 1 is a longitudinal 'sectional view through a propeller hub embodying the invention;

Fig. 2 is a longitudinal sectional view through the hydraulically operated pitch changing mechanism;

Fig. 3 Vis a view partly in elevation and partly f in transverse section taken on line 3-3 of Fig. 2;

Fig. 4 is a fragmentary detail view of the connection between the manually operable lever and the valve operating cams;

Fig. 5 is a fragmentary view partly in elevation and partly in transverse section taken on line 5-5 of Fig. 2 and illustrating the uid pressure control valves;

Fig. 6 is a similar view showing the valves in another position;

-' J Fig. '1 isa fragmentary transverse sectionalv view taken on line 1-1 of Fig. 2; and

Fig. 8 is a similar viewtaken on line 8--8 of Fig. 2 and illustrating the device for indicat- .ing the pitch of the propeller blades.

Referring to the drawings and particularly to Fig. 1 thereof, a variable pitch propeller of the pusher type constructed in accordance with the invention is shown as comprisinga hub I0 formed with a forward portion II and-an after portion I2 secured together and to a collar I3 i ,formed integrally with the after'section Ita of a Vmultipart drive shaft by longitudinally extending bolts I5.' The bolts I5 are formed duced threaded extremities I6 at each end, the forward extremities passing through a packing ring I1 which is secured in position therebyin abutting contact with the collar I3, thus preventing leakage at this point. The after extremities I6 of the bolts I5 pass through aV flange I8 formed on a hollow stream lined hub cap I9 and is secured thereto in abutting contact with after portion I2 of the hub by nuts 20. Leakage at this point is prevented by a grease ring 2| which is secured to the hub cap by screws 22.

'I'hc portions II and l2 of the hub are' formed with semicircular complementary recesses 23 in which the root portions 24 of a plurality of propeller blades 25 are mounted'for rotary adjustment about radially extending axes. Each of the blades 25 isformed with a collar 26 adjacent its root 24 which seats within a correspondingly shaped recess formed in the portions I I and I2 of the hub, thus reinforcing the blade and aii'ordling lateral and longitudinal stabilityfthereto.

The blades are each maintained against radial displacement by means of a collar 21 formed on the inner end of the root 24 and which is disposed within a longitudinal kslot 28 formed in the portions I I and I2 of the hub and a centrally disposed block 29 fixed to the shaft I4 by means of a key 30.

The blades 25 may be rotated a limited amount about their radial axes by means of a quill or torsion shaft 3l which extends coaxially through the drive shaft I4a. and is rotatable therein. A bevel pinion 32 is xed to the rear end of the quill shaft'3l and meshes with a segmented gear 33 provided on a ring 34 which is mounted on the collar 21 for rotary adjustment by means of key pins 35. Although the bevel gear 32, meshes with each of the segmental gears 33 so as to cause the propeller blades 25 to turn in unison when the pitch thereof is altered, additional means is provided to prevent binding of the parts which may be. caused by inltrations of sand and the like. This consists of an idle bevel gear 36 which is rotatably mounted on a reduced portion 31 of the block 29 for intermeshing engagement with segmental bevel gears 38 formed on the rings 34 opposite to the segmental gears 33. 'I'he construction hereinabove described is the subject of a copending application," Serial No. 224,068, filed August 10, 1938, now Patent No. 2,208,602.

'I'he section I4a. of the drive shaft is connected th ret with the forward section I4b thereof through the instrumentality of a hydraulically operated mechanismv which rotates the quill shaft 3l4 to alter the pitch of the propeller blades and which will now be described. The section |4b of the drive shaft is formed with an annular flange 39 which is connected with a flange 40 formed on one end of a cylindricaLhousing 4I `by means of la plu- A; rality of bolts 42 which pass through a series ofmeans of bolts 49 which pass through a ring.

- member 50 and a two part collar 5| disposed therebetween, the collar 48 transmitting'rotary motion to the section I4a and the two part collar 5| being formed with an internal annular shoulder 52 for engagement with an annular channel formed in the section |4a so as to prevent endwise movement of the parts. The elements are thus tied together for movement as a single unitary mass but aremade separately for convenience in manufacture and assembly. Fixed to the forward end of the quill shaft 3| by means of key screws 53 is a clutch member 54 which is formed with a plurality of circumferentially arranged integral splines 55 for interlocking engagement with corresponding grooves formed in a ring 56. This ring carries a plurality of piston vanes 51 at spaced intervals around its outer circumferential surface which extend into spaces between coacting fixed vanes 58 (Fig. 7) provided at intervals around the inner circumferential surface of the ring 50, there being suflicient space between the varies `51 and 58 to permit the clutch member 54 and quill shaft 3| to turn a limited amount. Leakage past the vanes 51 is prevented by suitable piston bars 59 mounted in slots formed therein and shaped to slidably receive them and spring pressed outwardly against the inner circumferential surface of ring 50. This structure functions as a cylinder and rotary piston.

The forward face of the clutch member 54 is formed with a plurality of clutch teeth 60 for engagement between similar clutch teeth on the opposed face of a plunger 6| which is splined as at 62 for axial sliding movement in a correspondingly splined ring 63 fixed in the rear end of the cylindrical housing 4| The plunger 6I is guided in its movement by a stud 64 engageable with a socket formed in the forward end of the quill shaft 3| and is provided with a forwardly extending stem 65, the extremity of which is xed in a follower plate 66. The plunger 6| is urged rearwardly and its teeth into engagement with the teeth of the member 54 so as to prevent the rotation of the quill shaft 3|, as will presently be described, by means of a coil spring 61. This spring bears against the plunger 6| and a seat 66 formed on a housing 69 which encloses the spring and is formed with a flange 10 at its rear end which is fixed to the rear end of the cylindrical housing 4|. The plunger 6| is at times forced forwardly against the action of the coil spring 61 so as to disengage its teeth from those of the member 54, by means of fiuid under pressure introduced into a metallic bellows 1| interposed between the follower plate 66 and the ange 10 of the spring housing 69.

The fluid, preferably oil, through which power is transmitted to the operating instrumentalities ofthe mechanism is forced through the system by means of a gear pump which comprises a plurality of gears 12 which are journalled on stud shafts 13 carried by the plate 43 for rotation within recesses 14 (Fig. 2) formed in the adjacent v plate 44. The teeth of the gears 12 are ground to conform closely to the walls of the recesses 14 to provide a substantially oil tight fit and mesh With. a single internal ring gear 15 mounted for relativev rotation on the outer circumference of the plate 44 between the plates 43 and 45. 'I'he teeth of the ring gear 15 also fit closely the circumferential surface of the plate 44 so as to minimize the leakage 4of oil therebetween in the manner of a gear pump. 'Ihe leakage of oil between the sides of the ring gear 15 and the plates 43 and 45 is' prevented by sealing rings 16 carried by these plates for engagement with grooves formed in the sides ofthe ring gear. The outer circumference of the ring gear 15 is grooved to receive a brake band 11 which may be actuated by any suitable means to retard or stop the rotation of the ring gear 15 so as to cause the rotation of the revolving gears 12 to pump fluid through the system.

Each of the gears 12 constitutes an oil pump in itself but is in fluid communication with the other gears so that they all function in unison to force oil through a plurality of parts and passages, presently to be described, in order to rotate the quill shaft 3| in opposite directions when it is desired to alter the pitch of the propeller blades. Associated with each of the gears 12 are two valve units 18 and 19 each comprising a sleeve valve member mounted in a radially extending bore 8| formed in the adjacent plate 46 and provided with a stem 82 having a conical head 83 at its outer end. 'I'he sleeve 80 is urged outwardly by a coil spring 84 interposed between a shoulder 85 of the bore and the head 83. The valves 18 and 19 are alternately depressed by means of oppositely inclined cam blocks 86 and 81 which are fixed to a ring 88. This ring is mounted for longitudinal sliding movement 4on an annular slide 89 fixed to the forward flange 40 of the housing 4| and is provided with a plurality of stop and guide pins 98 for engagement with longitudinally extending slots 9| formed in the slide 89. The ring 88 and the cam blocks 86 and 81 carried thereby may be shifted longitudinally in order to actuate the valve units 18 and 19, by means of a yoke 92 pivotally mounted on a fixed base, as at 93, and provided with an operating handle 94. This yoke is pivotally connected by bolts 95 at diametrically opposed points to a twopart annular shoe 96 which is engageable with an annular groove 91 formed in the outer circumference of the ring 88.

When the ring 88 and the cam blocks 86 and 81 occupy the positions shown in Fig. 2, and the drive shaft is rotating in the direction shown by the arrows in Fig. 3, the gears 12 will revolve bodily about the axis of the drive shaft, rotating the ring gear 15 with them about said axis. If the brake band 11 is now tightened the rotation of the ring gear 15 will be slowed down or stopped, thus causing the revolving gears 12 to also rotate about their own axes in the direction indicated by the arrows in. Fig. 3. This will cause them to draw oil from passageways 98 in the plate 45 (Fig. 2) and force it into passageways 99 formed in said plate parallel to the passageways 98. From here the oil iiows under pressure inwardly through radially extending passageways |00 in the plate 45 and thence rearwardly through a single passageway I 6I into the bellows 1|. This will cause the bellows to'expand and move the member 6| of the clutch forwardly and its teetl out of interlocking engagement with the teeth 60 of its coacting member 54. lAs the pressure of the 75 oil builds up in the system it will next be transmitted from-the radial passageways rear-v wardly through ports |02 into an annular groove I 83 formed in the rear face of the plate 45 and through ports |04 into the 'inner ends of the bores 8| of the valve units 18. From here the oil flows outwardly through the sleeve valve members 80, thence through port provided therein and into an annular groove |08 formed .in the forward' 51 together with the suction produced. by the gears 12 on the other side of the system displaces oil from the chambers |09 on the left hand sides of the vanes 51 and causes it to flow through passageways I0 in the housing 4| paralleling the passageways |01 therein and into radially extending passageways The oil next flows forwardly through -ports ||2 into an annular groove ||3 formed in the housing 4| concentric with the groove |05, thence through ports ||4 into the inner ends of the bores 8| of the valve units. 19, thence outwardly through elongated ports |I5' in the sleeve valve members 80 and ports ||5 provided in the plate 46 and into an annular groove I8 formed in the plate 45 concentric with the groove |03. The oil next flows through ports ||1 into radially extending passageways 8 and thence through vthe passageways 98 to the suction side of the gears 12. Oil is supplied to the system to compensate' for leakage from a sump or reservoir I9 formed in a tubular extension of the housing 4| which communicates with one ofthe passageways ||8 through a port |2|. The rapid rotation of the parts maintains the system completely filled with oil under centrifugal action. v

The pitch of the blades vof the propeller is determined by the rotary displacement of the quill shaft 3| with respect to the main drive shaft;r

and this is indicated visually by means of a stem |22 (Fig. 8) which is mounted for radial sliding movement in the drive shaft |4c and collar 5|. This stem is urged inwardly by means of a coil spring |23 and is provided with ahead |24 for engagement'with a cam |25 provided on the quill shaft 3|. When the amount that the stem |22 the desiredV pitch the brake band 11 is released so that the parts may again rotate in unison without. causing the gears 12 to pump oil. This will relieve the pressure within the bellows 1| and permit the coil spring 61 to move the clutch member 6| rearwardly so as to cause its teeth to mesh with the coacting teeth of the clutch member 54 on the quill shaft 3|. This locks the parts against any further relative rotation and maintains the propeller blades at the adjusted pitch.

If it is desired to adjust the pitch of the blades in an opposite direction the ring 88 is shifted to the left, as viewed in Fig. 2, so as to force the sleeve valve members 80 of the valve units 19 inwardly and permitting the sleeves of the valve units 18 to be moved outwardly by the coil springs 84. 'This will reverse the flow of the oil through the system and rotate the vanes 51, ring 58 and quill shaft 3| in a clockwise direction.

In the event that the operator fails to release thev brakeband -11 when the propeller blade reaches the limit of its turning or pitch changing movement, breakage of the parts caused by excessive oil` pressure is prevented by means of aA safety valve mechanism |28 (Fig. 3). This mechanism comprises a valve member |21 of the puppet type which is mounted in a bore 28 formed in the plate 45V and urged towards its seat |28 by a coil spring |30 interposed between the valve kmember |21 and a screw cap |3| threaded into the outer end of the bore |28. vThe valve member |21 controls communication between a passageway |32 which communicates through a port |33 with the annular channel |03, and the bore |28 which communicates through a port |34 with the annular channel ||8. If yexcess pressure should develop within the system, oil from the gear pumps 12 will flow throughfthe radial passageways |00v thence through the ports |02 into the annular passageway |03, thence through the port 9 |33 into the passageway |32 and unseat the valve |21 against the force of the spring |30. Theyoil will then flow past the valve member |21 and into the bore |28, thence through the port |34 into the annular channell 8, thence through the ports ||1 into the passageways ||8 and thence through the ports 98 back to the gear pumps 12 in a closed circuit.v It will be noted that the pressure of the oll in the system will not be decreased by the opening of the safety valve |28 but will remain at a maximum value determined by the strength of the spring |30.

Operation To summarize, the mechanism of this invention varies the pitch of a propeller by causing relative angular movement of a quill shaft with respect to a propeller shaft concentric therewith.` AThis angular movement is effected hydraulically by the operation of a planetary gear pump which forces oil into a bellows, thus declutching a clutch whichnormally prevents relative angular moverelative angular movement between the two shafts. Reversal'of` the fiow of oil, sending'it to the chambers formerly evacuated and evacuating projects shows that the propeller blades are at it from the chambers formerly filled is accomplished by the positioning of sleeve valves which govern the connection of various oil passages to the suction and delivery sides` of the oil pump. The positioning of the sleeve valves is governed by a ring-cam movable longitudinally of the shafts by manually operable means.

It will be understood that the above description and accompanying drawings comprehend only the general and preferred embodiment of the invention and that various changes in construction, proportion and arrangement of the parts may be made within the scope of the appended claims without sacrificing any of the advantages of the invention.

The invention described herein may be manufactured and/or used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

We claim:

l. A variable pitch propeller comprising a main drive shaft, a hub carried by said shaft, a blade mounted on said hub for adjustable rotation about a radially extending axis to vary the pitch thereof, a quill shaft extending through and rotatable in said drive shaft and operatively connected with said blade for rotating the same about said axis, fluid pressure operated means for rotating said quill shaft, pump means operable by the rotation of sai/d main drive shaft for operating said fluid pressure means and clutch mechanism also operable by said pump means for positively locking said drive shaft and said quill shaft against relative rotation to maintain said blade in its adjusted position.

2. A variable pitch propeller comprising a main drive shaft, a hub carried by said shaft, a blade mounted on said hub for adjustable rotation about a radially extending axis to vary the pitch thereof, a quill shaft extending through and rotatable in said drive shaft and operatively connected with said blade for rotating the same about said axis, fluid pressure operated means for rotating said quill shaft, a planetary gear pump operable by the rotationvof said main drive shaft for operating said fluid pressure means and clutch mechanism also operable by said pump means for positively locking said drive shaft and said quill shaft against relative rotation to maintain said blade in its adjusted position.

3. A variable pitch propeller comprising a main drive shaft, a hub carried by said shaft, a blade mounted on said hub for adjustable rotation about a radially extending axis to vary the pitch thereof, a quill shaft extending through and rotatable in said drive shaft and operatively connected with said blade for rotating the same about said axis, fluid pressure operated means for rotating said quill shaft, pump means operable by the rotation of saidI main drive shaft for operating said fluid pressure means, Valve means for controlling the direction of flow of fluid under pressure from said pump means to said fluid pressure operated means to reverse the direction of rotation of said quill shaft and the resulting pitch of said blade and clutch mechanism also operable by said pump means for positively locking said drive shaft and said quill shaft against relative rotation to maintain said blade in its adjusted position.

4. A variable pitch propeller comprising a main drive shaft, a hub carried by said shaft, a blade mounted on .said hub for adjustable rotation about a radially extending axis to vary the pitch thereof, a quill shaft extending through and rotatable in said drive shaft and operatively connected with said blade for rotating the same about said axis, fluid pressure operated means for rotating said quill shaft, pump means operable by the rotationof said main drive shaft for operating said uid pressure means, valve means for controlling the direction of rotation of said quill shaft and the resulting pitch of said blade, manually operable cam means for controlling the operation of said valve means and clutch mechanism also operable by said pump means for positively locking said' drive shaft and said quill shaft against relative rotation to maintain said blade in its adjusted position. v

5. A variable pitch propeller comprising a main drive shaft, a hub carried by said shaft, a blade mounted on said hub for adjustable rotation about a radially extending axis to vary the pitch thereof, a quill shaft extending through and rotatable in said drive shaft and operatively connected with said blade for rotating the same about said axis, fluid pressure operated means for rotating said quill shaft, pump means operable by the rotation of said main drive shaft for operating said fluid pressure means, clutch mechanism for releasably locking said quill'shaft in its adjusted position, and fluid pressure means for releasing said clutch mechanism.

6. A variable pitch propeller comprising a main drive shaft, a hub carried by said shaft, a blade mounted on said hub for adjustable rotation about a radially extending axis to vary the pitch thereof, a quill shaft extending through and rotatable in said drive shaft and operatively connected with said blade for rotating the same about said axis, fluid pressure operated means for rotating said quill shaft, pump means operable by the rotation of said main drive shaft for operating said fluid pressure means, clutch mechanism interposed between said drive shaft and said quill shaft, spring means for yieldably urging said clutch mechanism toward engaged position, and an expansible bellows operable by fluid pressure for disengaging said clutch mechanism to permit the rotary adjustment of said quill shaft relative to said drive shaft.

'7. A variable pitch propeller comprising a main drive shaft, a hub carried by said shaft, a blade mounted on said hub for adjustable rotation about a radially extending axis to vary the pitch thereof, a quill shaft extending through and rotatable in said drive shaft and operatively connected with said blade for rotating the same about said axis, fluid pressure operated means for rotating said quill shaft, pump means operable by the rotation of'said main drive shaft for operating said fluid pressure means, and a centrally located reservoir rotatable with said drive shaft for supplying under centrifugal action fluid to said fluid pressure operated means and said pumpl 

